Aerodynamic rotor blade

Abstract

The invention is related to a rotor blade for the generation of electrical power. The rotor blade transforms the kinetic energy of a fluid, into rotational movement of a mechanical shaft. The shape of the rotor blade is characterized in that, along an axis, it is longitudinally bound by a root (a) and a tip (b), which are connected through multiples curved segments, called neutral sectional axes [En i ]. All [En i ] generate a continuous or discontinuous curvature called Primary Neutral Axis [En]. The point corresponding to a leading edge and a trailing edge, configure an airfoil [PA ij ]. The curvature of the blade (e) has an arch of length L, and is defined by the neutral sectional axes [En i ]. The blade (e) is defined by at least one continuous curved section called primary neutral axis [En] having a length [L n ]. The blade's shape has a variable cross section along the Primary Neutral Axis [En].

The invention claimed is: 
     
       1. A blade for the generation of electrical power, from the transformation of kinetic energy of a fluid in rotation movement of the blade (e), wherein said movement is transmitted to a rotation axis coupled to said blade (e) located in an orthogonal framework of clearance planes formed by Cartesian axes [{right arrow over (X)} 0 ], [{right arrow over (Y)} 0 ] and [{right arrow over (Z)} 0 ], wherein:
 the rotation axis is coaxial relative to axis [{right arrow over (Z)} 0 ]; 
 the origin of the orthogonal framework of clearance planes formed by Cartesian axes [{right arrow over (X)} 0 ], [{right arrow over (Y)} 0 ] and [{right arrow over (Z)} 0 ] is located at the rotation axis and at the point wherein the rotation axis is coupled to the blade (e); 
 the blade (e) extends along axis [{right arrow over (Z)} 0 ], longitudinally bound by a root (a) and a tip (b), wherein root (a) is located by an auxiliary reference framework {right arrow over (X)} 1 {right arrow over (Y)} 1 {right arrow over (Z)} 1  which is parallel to the orthogonal framework of clearance planes formed by Cartesian axes [{right arrow over (X)} 0 ], [{right arrow over (Y)} 0 ] and [{right arrow over (Z)} 0 ]; 
 the root (a) and the tip (b) are connected through a series of sectional and constant curvatures called sectional neutral axes [En i ], which generate a continuous or discontinuous primary curvature called a primary neutral axis [En]; 
 the blade (e) has a cross-section limited by a leading edge (f) and a trailing edge (d), which upon joining leading edge (f) and the trailing edge (d) by means of continuous curves, configure an airfoil [PA ij ] having a bottom curve and a top curve; 
 the curvature of the blade (e) has a length L from the root (a) to the tip (b), which is between 0.01 m and 30 m, said curvature is formed by joining a series of points [Pc ij ], which are constructed over the bottom curve of the airfoil [PA ij ], at a distance of c/4 from the leading edge (f), where c is the chord length of the airfoil [PA ij ]; 
 the origin of the framework {right arrow over (X)} 1 {right arrow over (Y)} 1 {right arrow over (Z)} 1  is located in the point wherein said primary neutral axis [En] crosses the airfoil [PA ij ] at the root (a); 
 the blade's shape comprises a first geometrical variation corresponding to a change in the chord length c of the airfoil [PA ij ] along the primary neutral axis [En]; 
 the blade's shape comprises a second geometrical variation corresponding to an inclination varying along the primary neutral axis [En], said inclination is measured as a function of an inclination angle α ij  formed between the chord of each airfoil [PA ij ] and an axis u, wherein the axis u is perpendicular to a plane [P], and the plane [P] coincides with the {right arrow over (X)} 0 {right arrow over (Z)} 0  plane and intersects the primary neutral axis [En] at point [Pc ij ]; and 
 said inclination angle α ij  ranges between −31°≤α ij ≤30° at the root (a) and between −44°≤α ij ≤16° at the tip (b). 
 
     
     
       2. The blade (e) according to  claim 1 , wherein the blade (e) comprises three division sections of the primary neutral axis [En], called the first division section En 1 , the second division section En 2  and the third division section En 3 , wherein:
 first division section En 1  comprises a first sectional neutral axis [En 1 ] and has a length L 1 , which begins at the root (a) and ends at a point (2) located over the primary neutral axis [En], limited to a range between 0.15*L≤L 1 ≤0.25*L, 
 second division section En 2  comprises a second sectional neutral axis [En 2 ] and has a length L 2 , which begins at point (2) and ends at a point (3) located over the primary neutral axis [En], limited to a range between 0.3*L≤L 2 ≤0.5*L, 
 third division section En 3  comprises a third sectional neutral axis [En 3 ] and has a length L 3 , which begins at point (3) and ends at the tip (b), limited to a range between 0.3*L≤L 3 ≤0.5*; and 
 wherein the first division section En 1  is tangent to the second division section En 2  at point (2), and the second division section En 2  is tangent to the third division section En 3  at point (3). 
 
     
     
       3. The blade (e) according to  claim 2 , wherein the chord length c ranges between 0.05*L≤c 11 ≤0.3*L at the root (a) and between 0.01*L≤c 33 ≤0.3*L at the tip (b). 
     
     
       4. The blade (e) according to  claim 2 , wherein L 1  is 20% of L, L 2  is 40% of L, and L 3  is 40% of L. 
     
     
       5. The blade (e) according to  claim 2 , wherein:
 the first division section En 1  corresponds to the root zone, from which the blade attaches to a horizontal rotation axis, maintaining throughout the first division section En 1  sweep the shape of its airfoils [PA ij ]; 
 said root zone is a constant curve having a constant bending radius Rp 1 , which provides a focus located on plane [P] at a distance bound by a range between 1.3*L 1 ≤Rp 1 ≤57*L 1 ; 
 a first plane A is located at the root (a) and is perpendicular to the sectional neutral axis [En 1 ], said plane A provides an angle {right arrow over (X)}{right arrow over (Y)} 1 ° with plane {right arrow over (X)} 1  {right arrow over (Y)} 1  in the range 0°≤{right arrow over (X)}{right arrow over (Y)} 1 °≤90°; 
 said root zone comprises at least three (3) equidistant airfoils PA 11 , PA 12  and PA 13 , wherein each of these airfoils is located on a plane perpendicular to the sectional neutral axis [En 1 ], the first plane A located at the root (a) corresponds to airfoil PA 11 ; a second plane B located on the sectional neutral axis [En 1 ] at an intermediate point between the root (a) and point (2) belongs to the airfoil PA 12 ; and 
 a third plane D located at point (2) corresponds to the airfoil PA 13 , 
 said sectional neutral axis [En 1 ] corresponds to joining points Pc 11 , Pc 12  and Pc 13  located at a distance of c/4 from the leading edge (f) over the bottom curve of their corresponding airfoils PA 11 , PA 12  and PA 13  at planes A, B and D, respectively; 
 the transverse length of said root zone provides progressive and regressive changes or combinations thereof of the chord length c, ranging between 0.05*L≤c 11 ≤0.3*L; 0.046*L≤c 12 ≤0.3*L and 0.042*L≤c 13 ≤0.3*L; 
 each airfoil [PA ij ] making part of the root zone has an inclination angle α ij  (α 11 , α 12  and α 13 , respectively), wherein the inclination angle α ij  at the root (a) ranges between −31°≤α 11 ≤30° and the inclination angle α ij  at point (2) ranges between −34°≤α 13 ≤105°. 
 
     
     
       6. The blade (e) according to  claim 5 , wherein said angle {right arrow over (X)}{right arrow over (Y)} 1 °, with plane {right arrow over (X)} 1 {right arrow over (Y)} 1  ranges between 0°≤{right arrow over (X)}{right arrow over (Y)} 1 °≤40°. 
     
     
       7. The blade (e) according to  claim 6 , wherein said angle {right arrow over (X)}{right arrow over (Y)} 1 ° with plane {right arrow over (X)} 1 {right arrow over (Y)} 1  ranges between 10°≤{right arrow over (X)}{right arrow over (Y)} 1 °≤20°. 
     
     
       8. The blade (e) according to  claim 5 , wherein said chord length c undergoes a progressive change as it moves away from the root (a), said chord length c having a value of 0.082*L, 0.092*L, and 0.099*L, for airfoils PA 11 , PA 12  and PA 13 , respectively. 
     
     
       9. The blade (e) according to  claim 5 , wherein the inclination angle α ij  at the root (a) ranges between 5°≤α 11 ≤25° and the inclination-angle α ij  at point (2) ranges between 1°≤α 13 ≤19°. 
     
     
       10. The blade (e) according to  claim 2 , wherein:
 the second division section En 2  corresponds to the internal zone, maintaining throughout its sweep the shape of its airfoils [PA ij ]; 
 said internal zone is a constant curve having a constant bending radius Rp 2  which has a focus located on plane [P] at a distance bound by a range 1*L 2 ≤Rp 2 ≤5*L 2 ; 
 said internal zone comprises at least three (3) equidistant airfoils PA 21 , PA 22  and PA 23 , wherein each of these airfoils is located on a plane perpendicular to the sectional neutral axis [En 2 ], a first plane E located at point (2) corresponds to airfoil PA 21 ; a second plane F located on the sectional neutral axis [En 2 ] at an intermediate point between point (2) and point (3) belongs to the airfoil PA 22 ; and a third plane G located at point (3) corresponds to the airfoil PA 23 ; 
 said sectional neutral axis [En 2 ] corresponds to joining points Pc 21 , Pc 22  and Pc 23  located at a distance of c/4 from the leading edge (f) over the bottom curve of their corresponding airfoils PA 21 , PA 22  and PA 23  at planes E, F and G, respectively; 
 the transverse length of this internal zone provides progressive and regressive changes or combinations thereof of the chord length c, ranging between 0.042*L≤c 21 ≤0.3*L, 0.034*L≤c 22 ≤0.3*L and 0.026*L≤c 23 ≤0.3*L; 
 each airfoil [PA ij ] making part of the internal zone has an inclination angle α ij  (α 21 , α 22  and α 23 , respectively), wherein the inclination angle α ij  at point (2) ranges between −34°≤α 21 ≤105° and the inclination angle α ij  at point (3) ranges between −41°≤α 23 ≤60°. 
 
     
     
       11. The blade (e) according to  claim 10 , wherein said transverse length of said internal zone comprises a first progressive change in the length of chord length c from point (2) up to an inflection point located on plane F at the middle of the sectional neutral axis [En 2 ], and a second regressive change in the length of chord length c until point (3), said chord length c having a value of 0.099*L, 0.104*L, and 0.094*L, for airfoils PA 21 , PA 22  and PA 23 , respectively. 
     
     
       12. The blade (e) according to  claim 10 , wherein the inclination angle α ij  at point (2) ranges between 1°≤α 21 ≤19° and the inclination angle α ij  at point (3) ranges between −5°≤α 23 ≤13°. 
     
     
       13. The blade (e) according to  claim 2 , wherein:
 the third division section En 3  corresponds to the external zone, maintaining throughout its sweep the shape of its airfoils [PA ij ]; 
 said external zone is a constant curve having a constant bending radius Rp 3 , which has a focus located on plane [P] at a distance bound by a range between 1*L 3  Rp 3 ≤12*L 3 ; 
 said external zone comprises at least three (3) equidistant airfoils PA 31 , PA 32  and PA 33 , wherein each of these airfoils is located on a plane perpendicular to the sectional neutral axis [En 3 ], a first plane H located at point (3) corresponds to airfoil PA 31 , a second plane I located on the sectional neutral axis [En 3 ] at an intermediate point between point (3) and the tip (b) belongs to the airfoil PA 32 , and a third plane J located at the tip (b) corresponds to the airfoil PA 33 ; 
 said sectional neutral axis [En 3 ] corresponds to joining points Pc 31 , Pc 32  and Pc 33  located at a distance of c/4 from the leading edge (f) over the bottom curve of their corresponding airfoils PA 31 , PA 32  and PA 33  at planes H, I and J, respectively; 
 the transverse length of this external zone provides progressive and regressive changes or combinations thereof of the chord length c, ranging between 0.026*L≤c 31 ≤0.3*L, 0.018*L≤c 32 ≤0.3*L and 0.01*L≤c 33 ≤0.3*L; 
 each airfoil [PA ij ] making part the external zone has an inclination angle α ij  (α 31 , α 32  and α 33 , respectively), wherein inclination angle α ij  at point (3) ranges between −41°≤α 31 ≤60° and the inclination angle α ij  at the tip (b) ranges between −44°≤α 33 ≤16°. 
 
     
     
       14. The blade (e) according to  claim 13 , wherein chord length c undergoes a regressive change as it moves away from point (3), said chord length c having a value of 0.094*L, 0.080*L, and 0.070*L, for airfoils PA 31 , PA 32  and PA 33 , respectively. 
     
     
       15. The blade (e) according to  claim 13 , wherein the inclination angle α ij  at point (3) ranges between −5°≤α 31 ≤13° and the inclination angle α ij  at the tip (b) ranges between −5°≤α 33 ≤15°. 
     
     
       16. The blade (e) according to  claim 2 , wherein a tangent line at the tip (b) is at most, perpendicular to the rotation axis {right arrow over (Z)} 0  when the blade shows its greatest curvature according to the combination of bending radius Rp 1 , Rp 2  and Rp 3  of the division sections En 1 , En 2  and En 3 , wherein:
 Rp 1  is the constant bending radius of the first division section En 1  having a focus located on plane [P] at a distance bound by a range between 1.3*L 1 ≤Rp 1 ≤57*L 1 ; 
 Rp 2  is the constant bending radius of the second division section En 2  having a focus located on plane [P] at a distance bound by a range between 1*L 2 ≤Rp 2 ≤5*L 2 ; 
 Rp 3  is the constant bending radius of the third division section En 3  having a focus located on plane [P] at a distance bound by a range between 1*L 3 ≤Rp 3 ≤12*L 3 . 
 
     
     
       17. The blade (e) according to  claim 1 , wherein said inclination angle α ij  ranges between 5°≤α ij ≤25° at the root (a) and between −5°≤α ij ≤15° at the tip (b).